Fix Tcg2SubmitCommand in TPM field upgrade scenario.

There's a bug that after the device was forced shut down during the tpm
firmware update process, then the TPM will stay in field upgrade mode and
refuse to work properly. This will block TPM startup and cause the device
to bootloop.

Now in the TCG_DXE_DATA struct we don’t have a flag to indicate the current
TPM mode, and we will simply treat the upper Scenario with this DEVICE_ERROR
and set the TPMPresentFlag to FALSE.

Later in Tcg2SubmitCommand we will just return DEVICE_ERROR and skip the
actual TPM recovery.

We should have an extra flag that check for the TPM response code and if
it's TPM_RC_UPGRADE, we knew the device is in field upgrade mode and should
continue the workflow.

We should only return EFI_DEVICE_ERROR when both TPMPresentFlag and
TpmUpdateFlag are false.

The field upgrade is part of TCG spec, and the capsule update/recovery
is part of UEFI spec.
Make this PR to bring in the fix for this corner case.

Signed-off-by: Liqi Qi <[email protected]>

Author: liqiqiii

SecurityPkg/Tcg/Tcg2Dxe/Tcg2Dxe.c

@@ -81,6 +81,7 @@ typedef struct {
 
 typedef struct _TCG_DXE_DATA {
   EFI_TCG2_BOOT_SERVICE_CAPABILITY    BsCap;
+  BOOLEAN                             TpmUpdateFlag;
   TCG_EVENT_LOG_AREA_STRUCT           EventLogAreaStruct[TCG_EVENT_LOG_AREA_COUNT_MAX];
   BOOLEAN                             GetEventLogCalled[TCG_EVENT_LOG_AREA_COUNT_MAX];
   TCG_EVENT_LOG_AREA_STRUCT           FinalEventLogAreaStruct[TCG_EVENT_LOG_AREA_COUNT_MAX];
@@ -101,6 +102,7 @@ TCG_DXE_DATA  mTcgDxeData = {
     0,                                         // NumberOfPCRBanks
     0,                                         // ActivePcrBanks
   },
+  FALSE,
 };
 
 UINTN   mBootAttempts  = 0;
@@ -1407,6 +1409,8 @@ Tcg2SubmitCommand (
   )
 {
   EFI_STATUS  Status;
+  TPM_RC      ResponseCode;
+  UINT32      CurrentOutputBlockSize;
 
   if ((This == NULL) ||
       (InputParameterBlockSize == 0) || (InputParameterBlock == NULL) ||
@@ -1415,10 +1419,6 @@ Tcg2SubmitCommand (
     return EFI_INVALID_PARAMETER;
   }
 
-  if (!mTcgDxeData.BsCap.TPMPresentFlag) {
-    return EFI_DEVICE_ERROR;
-  }
-
   if (InputParameterBlockSize > mTcgDxeData.BsCap.MaxCommandSize) {
     return EFI_INVALID_PARAMETER;
   }
@@ -1427,13 +1427,53 @@ Tcg2SubmitCommand (
     return EFI_INVALID_PARAMETER;
   }
 
-  Status = Tpm2SubmitCommand (
-             InputParameterBlockSize,
-             InputParameterBlock,
-             &OutputParameterBlockSize,
-             OutputParameterBlock
-             );
-  return Status;
+  //
+  // Always attempt to submit the command, but if the TPM is already flagged
+  // as not present, we expect it to fail other than the capsule update scenario.
+  //
+  CurrentOutputBlockSize = OutputParameterBlockSize;
+  Status                 = Tpm2SubmitCommand (
+                             InputParameterBlockSize,
+                             InputParameterBlock,
+                             &CurrentOutputBlockSize,
+                             OutputParameterBlock
+                             );
+  if (EFI_ERROR (Status)) {
+    return mTcgDxeData.BsCap.TPMPresentFlag ? Status : EFI_DEVICE_ERROR;
+  }
+
+  if (CurrentOutputBlockSize < sizeof (TPM2_RESPONSE_HEADER)) {
+    DEBUG ((DEBUG_ERROR, "%a: Response buffer too small!\n", __func__));
+    return EFI_DEVICE_ERROR;
+  }
+
+  //
+  // Correctly read the response code and swap bytes from Big-Endian to Host order.
+  // The responseCode field is at offset 6 of the response header.
+  //
+  ResponseCode = SwapBytes32 (ReadUnaligned32 ((UINT32 *)(OutputParameterBlock + 6)));
+  DEBUG ((DEBUG_ERROR, "Response code is %x", ResponseCode));
+  // If the response code ever equals to TPM_RC_UPGRADE, it means the TPM is in field
+  // upgrade mode, we set both flags to TRUE.
+  if (ResponseCode == TPM_RC_UPGRADE) {
+    DEBUG ((DEBUG_INFO, "TPM response code TPM_RC_UPDATE received. Setting flag.\n"));
+    mTcgDxeData.TpmUpdateFlag        = TRUE;
+    mTcgDxeData.BsCap.TPMPresentFlag = TRUE;
+  }
+
+  // Now that we have set the TPMPresentFlag, it should be able to reflect the actual TPM presence.
+  if (!mTcgDxeData.BsCap.TPMPresentFlag) {
+    DEBUG ((DEBUG_WARN, "%a: TPMPresentFlag is FALSE. Expecting command to fail.\n", __func__));
+    return EFI_DEVICE_ERROR;
+  }
+
+  // If the response code is not TPM_RC_SUCCESS and the device is not in field update mode, return error.
+  if ((ResponseCode != TPM_RC_SUCCESS) && (mTcgDxeData.TpmUpdateFlag == FALSE)) {
+    DEBUG ((DEBUG_ERROR, "%a: Command failed with response code 0x%x\n", __func__, ResponseCode));
+    return EFI_DEVICE_ERROR;
+  }
+
+  return EFI_SUCCESS;
 }
 
 /**